Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment
A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allows its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt.
- Research Organization:
- Battelle Pacific Northwest Labs., Richland, WA (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6346346
- Report Number(s):
- PNL-3569; ON: DE81026840; TRN: 81-015218
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CAST IRON
CORROSION RESISTANCE
CREVICE CORROSION
PITTING CORROSION
STRESS CORROSION
RADIOACTIVE WASTE DISPOSAL
ENGINEERED SAFETY SYSTEMS
TITANIUM ALLOYS
BACKFILLING
BASALT
GEOLOGIC DEPOSITS
GROUND WATER
UNDERGROUND DISPOSAL
ALLOYS
CARBIDES
CARBON COMPOUNDS
CHEMICAL REACTIONS
CORROSION
HYDROGEN COMPOUNDS
IGNEOUS ROCKS
IRON ALLOYS
IRON BASE ALLOYS
IRON CARBIDES
IRON COMPOUNDS
MANAGEMENT
OXYGEN COMPOUNDS
ROCKS
TRANSITION ELEMENT COMPOUNDS
VOLCANIC ROCKS
WASTE DISPOSAL
WASTE MANAGEMENT
WATER
360105* - Metals & Alloys- Corrosion & Erosion
052002 - Nuclear Fuels- Waste Disposal & Storage